1. Field of the Invention
The present invention relates an apparatus and a method of detecting the home position of a carriage.
2. Description of Related Art
In a typical serial printer such as an ink jet printer, a recording head scans on a printing paper to print. This recording head is fixed to a carriage to move with the carriage. This carriage is driven by a DC(Direct Current) motor. The system for driving the carriage is as follows.
First, a timing belt is stretched at a predetermined tension between a driving pulley, which is fixed to the rotating shaft of the DC motor, and a driven wheel which is a companion to the driving pulley. The carriage is mounted on the timing belt. Thus, the carriage is driven by the rotation of the DC motor so as to move main scanning directions.
For such ink jet printers, the location of a carriage at its home position or another at power-on affects maintenance of the printers.
The location of a carriage located at the home position at power-on indicates that the previous printing process finished in which an ink-injecting nozzle has been covered with a cap.
On the other hand, the location of a carriage located at another other than the home position at power-on indicates that the previous printing process finished in which an ink-injecting nozzle has not been covered with a cap, thus requiring sucking-up ink from the nozzle before printing.
Ink jet printers have employed a sensor for solo use in detecting the position of a carriage at the home or another position. Such a sensor is not so expensive, however, a manufacturing cost is high for a large number of printers to be shipped with such sensors.
It is therefore an object of the present invention to eliminate the aforementioned problems and to provide an apparatus and a method of detecting the home position of a carriage with a low cost of printer manufacture, and a storage medium storing a home position detecting program.
The present invention provides an apparatus for detecting a home position of a carriage including: a position detecting part to detect a position of a carriage driven by a motor; a first drive control part to control the motor so that the carriage is transferred toward a frame of a printer until being stopped, the frame being provided at a home position range side; a second drive control part to control the motor so that the carriage is transferred toward another frame of the printer until being stopped, the other frame being provided opposite to the frame provided at the home position range side; a third drive control part to control the motor so that the carriage is transferred to a predetermined position close to the home position range; and a selection control part to select one of the first, the second, and the third drive control parts and control the selected drive control part, thus detecting a home position of the carriage based on a result of the selective control and the output of the position detecting part.
The apparatus for detecting a home position of a carriage as configured above is capable of home position detection with no detector for solo use in home position detection, thus achieving less manufacturing cost.
Furthermore, the present invention provides a method of detecting a home position of a carriage including the steps of: a first step of transferring a carriage driven by a motor toward a frame of a printer until being stopped, the frame being provided at a home position range side; a second step of obtaining a first stop position at which the carriage stops by the first step and a first transfer distance from a position at which the carriage starts to transfer to the first stop position, based on an output of a position detecting part for detecting a position of the carriage; a third step of transferring the carriage toward another frame of the printer until being stopped, the other frame being provided opposite to the frame provided at the home position range side; a fourth step of obtaining a second stop position at which the carriage stops by the third step and a second transfer distance in which the carriage transfers from the first stop position to the second stop position, based on the output of the position detecting part; and a fifth step of setting an initial position of the carriage in the home position range based on the second transfer distance and the first stop position.
The method of detecting a home position of a carriage as configured above is capable of home position detection with no detector for solo use in home position detection, thus achieving less manufacturing cost.
Moreover, the present invention provides a computer-readable storage medium storing program code for detecting a home position of a carriage, including: first program code means for transferring a carriage driven by a motor toward a frame of a printer until being stopped, the frame being provided at a home position range side; second program code means for obtaining a first stop position at which the carriage stops by the first program code means and a first transfer distance from a position at which the carriage starts to transfer to the first stop position, based on an output of a position detecting part for detecting a position of the carriage; third program code means for transferring the carriage toward another frame of the printer until being stopped, the other frame being provided opposite to the frame provided at the home position range side; fourth program code means for obtaining a second stop position at which the carriage stops by the third program code means and a second transfer distance in which the carriage transfers from the first stop position to the second stop position, based on the output of the position detecting part; and fifth program code means for setting an initial position of the carriage in the home position range based on the second transfer distance and the first stop position.